Construction of Stable Zn Anode by 3D Flamed Reduced Graphene Oxide with Long Cycling Life

Aqueous zinc-ion capacitors (ZICs) have been regarded as an emerging energy storage device due to their excellent safety, low cost, environmental friendliness, and high energy density. However, poor cycling stability due to fatal defects of the zinc anode such as dendrite growth, corrosion, and passivation limits the better development of ZICs. Here, we propose a dual strategy of 3D host design and surface chemical modification. Zn foam is chosen as the anode skeleton to expand the 2D zinc metal into a 3D porous structure, providing abundant active sites and enhancing the electrical conductivity. Meanwhile, the flamed reduced graphene oxide (FRGO) coating is used as a protective and modulating layer for the 3D skeleton to enhance zinc deposition and effectively inhibit interfacial side reactions. As a verification, the prepared FRGO coated Zn foam (FRGO@Zn foam) in a symmetrical cell shows a stable cycle life of 1600 h at 1 mA cm^–2 and 1 mAh cm^–2. Furthermore, when FRGO@Zn foam was used as the anode and dense rGO/FRGO graphene film used as the cathode, the energy density of the ZICs is as high as 118.4 Wh L^–1 (124.6 Wh kg^–1), and the capacitance retention rate is still 93.6% after 30,000 cycles, indicating that the anode has good application prospects in the ZIC field.